8C=8/3.7.11+8/7.11.15+8/11.15.19+8/15.19.23+8/19.23.27+8/23.27.31
8C=1/3.7-1/7.11+1/7.11-1/11.15+1/11.15-1/15.19+1/15.19-1/19.23+1/19.23+-1/23.27-1/27.31
8C=1/3.7-1/27.31
8C=1/21-1/837
8C=272/5859
C=34/5859
A = 1/3 3/3.7 5/3.7.11 7/3.7.11.15 ... 2021/3.7.11...4043 chứng minh A<1/2
Cho S=1/3+3/3.7+5/3.7.11+7/3.7.11.15+...+2n+1/3.7.11...(4n+3),với n thuộc N*.Chứng minh rằng S<1/2
Giúp mình với,mình đang cần gấp
1, Tìm x
a, 4x - (7+ 5x) = 15 + (-29)
b,\(\frac{x}{11}=\frac{x+4}{33}\)
2. Rút gọn
a, \(\frac{3.7.11}{33\cdot9}\)
b,\(\frac{5^3.2^4}{4.10^2.11}\)
c.\(\frac{8.5-8.2}{32}\)
hãy chứng minh rằng abc.7.11.15=abcabc
Rút gọn các phân số sau:
a ) 3.7.11/22.9
b) 49.7+49/10
c) 12.5-9.12/32.6
C=(1+1/1×3)(1+12×4)(1+1/3×5)...(1+1/2014×2016)
Tính C
C=(1+1/1*3)*(1+1/2*4)*(1+1/3*5)...(1+1/2014*2016).tim gia tri cua c
tính
a; A = 3/4 * 8/9 * 15/16 * ..............* 9999/10000
b; B = {1 - 1/21 } * { 1 - 1/28 } * {1 - 1/36 } * .......................*{ 1 - 1326}
c; C = { 1 + 1/1*3 } * { 1 + 1 / 2*4 } * { 1 + 1/3*5} * ...........................* { 1+ 1/99*101}
Tìm C biết C=1+1/2x(1+2)+1/3x(1+2+3)+1/4x(1+2+3+4)+......+1/16x(1+2+3+4+...+16)